The Most Important Argument in Christian Apologetics: C. S. Lewis' Trilemma Proving the Divinity of Christ

Christ either deceived mankind by conscious fraud, or He was Himself deluded and self-deceived, or He was Divine. There is no getting out of this trilemma. It is inexorable.

In his seminal work Mere Christianity, Lewis further elaborates his argument outlined here:

I am trying here to prevent anyone saying the really foolish thing that people often say about Him: I’m ready to accept Jesus as a great moral teacher, but I don’t accept his claim to be God. That is the one thing we must not say. A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher. He would either be a lunatic — on the level with the man who says he is a poached egg — or else he would be the Devil of Hell. You must make your choice. Either this man was, and is, the Son of God, or else a madman or something worse. You can shut him up for a fool, you can spit at him and kill him as a demon or you can fall at his feet and call him Lord and God, but let us not come with any patronising nonsense about his being a great human teacher. He has not left that open to us. He did not intend to. ... Now it seems to me obvious that He was neither a lunatic nor a fiend: and consequently, however strange or terrifying or unlikely it may seem, I have to accept the view that He was and is God.

Lewis' trilemma has had an enormous impact on modern Christian apologetics. In Part 2, we will investigate the argument further.